Culture
Easily grown in average, dry to medium, well-drained soil in full sun to part shade. Prefers full sun. Tolerates a wide range of soil conditions including poor, dry soils, but must have good drainage. Plants tend to be biennials or short-lived perennials. Remove spent flower spikes before seed sets to encourage additional bloom and to stimulate perennial tendencies. However, it is usually best to leave some flower spikes for self-seeding or for seed propagation in order to insure than the plants will remain in the garden. May also be propagated by root cuttings in early spring.
Noteworthy Characteristics
Verbascum is a genus of about 350 species of mostly biennial plants but also some annuals, perennials and sub-shrubs. They are native from Europe to North Africa to Western and Central Asia. They are grown for their attractive flower spikes.
The genus name Verbascum comes from the Latin word barbascum which means "bearded", in reference to the hairy stamen filaments of some species.
'Banana and Custard' is a hybrid mullein cultivar. It is an erect, clump-forming biennial which usually will remain in the garden through self-seeding. Forms a large basal rosette (to 2' wide) of woolly, ovate, silvery-green leaves from which rise multiple, erect flowering stems (3-4' tall) bearing long terminal spikes of large, 5-lobed, nearly flat, bright two-toned yellow flowers (to 2" diameter). Long, late spring to summer bloom period with possible fall rebloom. Though almost universally sold as 'Banana Custard' the Royal Horticulture Society lists the correct name as 'Banana and Custard.'
Problems
Susceptible to spider mites in hot conditions. Taller plants and those grown in rich, fertile soils may need staking or other support. Wet, poorly drained soils are usually fatal. Deer tend to avoid this plant.
Uses
Borders and cottage gardens. Good vertical accent. Grows well in poor soils and will grow well on dry, rocky slopes or scree. Shorter cultivars can be effective in containers.